Defendant Jodi Arias listens to defense attorney Kirk Nurmi make his closing arguments during her trial on Friday, May 3, 2013 at Maricopa County Superior Court in Phoenix, AZ. Arias is charged with first-degree murder. / Rob Schumacher, The Arizona Republic

by Michael Kiefer, The Arizona Republic

by Michael Kiefer, The Arizona Republic

PHOENIX -- Was it murder or self-defense? That is the question the Jodi Arias jury must answer.

Arias claims that her secret boyfriend Travis Alexander physically, emotionally and sexually abused her over the two years of their relationship, and that she killed him when he became enraged and attacked her because she had dropped his expensive camera while photographing him in the shower.

Prosecutor Juan Martinez, on the other hand, claims that Arias stole a gun from her grandfather - it has never been found - and drove from northern California to Mesa with the express purpose of murdering Alexander. She was angry that he was taking another woman on vacation to Mexico, Martinez claims, and she killed Alexander in cold blood, first stabbing him, then cutting his throat, and as he lay dead or dying on the floor, shooting him in the head.

In addition to acquittal, here are the jury's options as they begin to deliberate the case:

First-degree murder

Arias is charged with two theories of first-degree murder to double the chances of getting that conviction.

The first charge is premeditated murder, and Martinez put forth circumstantial evidence to try to convince the jury:

â?¢ Arias dyed her hair to disguise herself before she drove to Mesa; her attorneys said she did so long before the trip.

â?¢ Arias rented a car to avoid detection and didn't want red, which might attract police attention; she and her attorneys claimed she did so because her own car couldn't make the drive.

â?¢ She removed the front license plate of the rental car and attached the rear plate upside down to avoid detection. (But wouldn't that make her more likely to be pulled over? In fact, she was pulled over in Utah for that reason.)

â?¢ She brought two, or maybe three, gas cans in her car to avoid a paper trail of gas receipts in Arizona; Arias claimed she was afraid of running out of gas in remote areas, such as the national parks she planned to visit to add to her photographer's portfolio.

â?¢ And the missing gun, which was the same caliber as the gun that killed Alexander: Arias claims she pulled Alexander's own gun from the top shelf of his closet. Martinez pointed out that none of Alexander's friends knew him to have a gun.

â?¢ Furthermore, the fact that there were three potentially fatal wounds - one stab wound, the gunshot and the slit throat - could indicate that Arias had enough time to reflect on what she was doing. That in itself could be considered premeditation.

The second theory of first-degree murder, felony murder, is more complicated. Alexander died during the commission of a burglary, Martinez claims. In legal terms, "burglary" is not breaking and entering, as most people think.

To be exact, it means that a person entered a premises with the intention of committing another felony, which in this case was murder. And though Arias was invited to Alexander's house to have sex, according to Martinez's theory, permission to be there ended the instant that the murder began, thus making her a burglar.

The jury does not have to unanimously agree on one theory or the other. Some may opt for premeditated murder, and the rest for felony murder, and as long as all 12 sitting jurors chose one or the other form of first-degree murder, the verdict is considered unanimous.

If they find Arias guilty of first-degree murder, the trial will move to a new phase with new witnesses and arguments so that the jury can decide whether Arias deserves the death penalty.

Lesser charges

The defense is asking the jury to acquit Arias on grounds of self defense; it is more likely that her attorneys hoped for the jury to decide that Arias had committed a lesser form of murder.

Second-degree murder, for example, means there was no premeditation, and carries a prison sentence of 10 to 22 years; manslaughter, meaning Arias killed Alexander in a moment of passion, calls for a prison sentence of seven to 21 years.

If the jury chooses any of those options, they may be asked to deliberate briefly on whether there are aggravating circumstances that would allow the judge to impose the harshest sentence. Then the trial would be over and the judge would set a sentencing date a month or so later.

Mistrial

In cases such as this, juries are supposed to first consider first-degree murder, and if they can't agree, are then supposed to consider second-degree murder.

If they can't agree on that verdict, they are supposed to move down to manslaughter.

Or they can agree to disagree.

Juror questions over the course of the trial have indicated that the jurors are not in full agreement on every issue. It only takes one juror to cause a hung jury.

If the jurors arrive at an impasse, a mistrial would be declared.

Then the Maricopa County Attorney's Office would have to decide whether to retry the case at an additional cost of millions of dollars or to enter into a plea agreement with Arias, who was willing to settle on second-degree murder before trial began.